Cut/sore on penis

My boyfriend has been complaining of a broken penis - lol. He doesn't like discussing in great detail (we've only been together a couple of months so I guess this is part of his issue about talking about it in too much detail!) but from what he has said I get the understanding that he has something like a small cut or a sore on the head of his penis where it joins the foreskin, he said it hurts when he pulls the foreskin back to wash.
I am his first girlfriend so we've been putting it down to him having regular sex which he's never experienced before, however I am worried that it might be something I am doing to him which is causing this. We tried to agree to not have sex until he's healed, but every time he thinks it is it gets sore again after sex.
He has been tested to STD's and doesn't have any, I've never been tested but have only ever slept with one person (and that person had only ever slept with me) and we always used condoms. Does anyone know what could be causing this and how long it will take to heel.
Many thanks

it depends on what is happening. often, the frenulum, (that thin piece of skin which is on the underside of the penis, and goes from just under the urinary opening, and spreads out to join the shaft) tears. when it does, it is often painful, and takes a while to heal. if you masturbate or have sex too soon, it tears again, delaying the healing.
if it is something else, I don't know what to tell you.